1. Field of Invention
The present invention relates to a communication system, and more particularly to a GPS microphone for a communication system, wherein the GPS microphone is capable of sending out positioning data in form of an audio signal to a control center such that the GPS microphone supports both the communication provision and the position location provision.
2. Description of Related Arts
Communication devices, such as cellular phone, satellites phone and “Pocket PC”, are considered as one of the common communication tools, wherein a user is able to wirelessly communicate with another user via the communication device via a public network. A communication device generally comprises a speaker microphone and a wireless (codec) |modem| such as RF transmitter/receiver connected with the speaker microphone in such a manner that when the speaker microphone receives an audio signal, the audio signal is encoded to a digital data and sent out in a wireless manner.
Nowadays, the communication devices are incorporated with a Global Positioning System (GPS) for tracking the location of the user, wherein the common GPS generally comprises a built-in GPS receiver equipped with the modem to wirelessly send out a positioning data from the communication device. In order to receive the GPS positioning data, the communication device must employ a processor unit arranged in such a manner that after the processor unit receives the positioning data, the positioning data is decoded to a readable data so that the user is able to locate the position of the sender.
However, such GPS incorporated with the communication device has several drawbacks. The communication device must be employed with the modem for wirelessly transmitting both the audio signal and the positioning data, which will highly increase the manufacturing cost of the communication device. Furthermore, the data transmission speed of the modem is inconsistent such that there is always a delay when both the audio signal and the positioning data are sent out.
In addition, existing lower-end radio systems do not support position location provisions, although providing a remote user's position to a base station would be very desirable to enable tracking of the remote user, particularly through the use of the Global Positioning Satellite (GPS) system. Therefore, the GPS must be independently installed to provide positioning data.
For example, while patrolling, police officers or security officers generally must arm with a radio frequency communication device to keep contact with the control center. For safety and arrangement purpose, their locations are preferred to be tracked by the control center so that the control center can give assistance to them in case of emergency. However, the police officers or the security officers must carry an additional GPS device in order to send out the positioning signal to the control center. In other words, the additional GPS device will increase the load of the police officers or the security officers while patrolling.